The £55.7 billion project to build a new high speed rail line is at risk of "fraud and other financial errors" because of a lack of basic financial controls.
This is the damning verdict delivered by MPs investigating the HS2 line, which is due to run between Birmingham, London, Manchester and Leeds.
They held an inquiry after the National Audit Office, the official spending watchdog,discovered that taxpayers handed over £1.76 million in unauthorised redundancy payments to staff working for HS2 Ltd, the Government-owned business building the new line.
HS2 Ltd offered staff compulsory and voluntary redundancy schemes at enhanced terms, well in excess of those authorised by the Department for Transport (DfT).
But it should have stuck to the DfT's guidelines.
The Commons Public Accounts Committee has now issued a damning verdict in a new report, describing the payments as "a shocking waste of taxpayers’ money".
And they said: "There is no means for these sums to be recovered.
"The unauthorised schemes were able to proceed because weak internal processes at HS2 Ltd prevented key decision-making and scrutiny bodies from receiving accurate information."
But the MPs also warned that poor financial controls could lead to more problems in the future.
They said: "HS2 Ltd lacks basic financial controls in other important areas, heightening the risk of fraud and financial errors such as duplicate payments.
"This situation is exacerbated by an excessively high rate of staff turnover."
The conclusions were published in a report by the Committee, which includes Birmingham MP Shabana Mahmood (Lab, Birmingham Ladywood).
The MPs said the Department for Transport and HS2 Ltd needed to address HS2 Ltd's failings "as a matter of urgency".
And they said the DfT is failing to control the business. Simon Kirby, the Chief Executive of HS2 Ltd when the payments were made "has not been held to account for his actions", the MPs said.
HS2 has been controversial since the project began. The Government says it is evidence of investment in infrastructure which will help to grow the economy in the Midlands and the North, but critics claim it offers poor value for money.
The construction of two new rail stations dedicated to HS2 trains, in Curzon Street, Birmingham city centre, and near Birmingham Airport, has helped attract investment for urban regeneration and local transport projects in the surrounding areas.
A DfT spokesperson said: “We have made clear to HS2 Ltd in the strongest terms that we expect them to always meet their obligations and responsibilities to the taxpayer.
“As the NAO said this was a failure in the internal process at HS2 Ltd that resulted in these payments being made without approval in place.
“The Department has received legal advice that bringing a claim against Mr Kirby for breaching his duties and responsibilities as CEO and director of HS2 Ltd would not be justified.”